A top level player on online games. Shitbucket is used to describe the players lifestyle, not having time in their life to do anything but play games, even having time to take a shit, hence the Shit-Bucket.

The shitbucket on the other team went 263-2 in the Viper and TV'ed 41 Jets.

an annoying person, usually referred to as "stupid", or "get away from me (persons name here) can be used as an insult or as a friendly jest. Someone whos done something stupid. Literally "you have stepped in a bucket of shit " from the days in which people didnt have toilets. A witty remark.